1. Field of the invention
The present invention concerns a cable comprising a small number of optical fibers that has a very simple structure and consequently is very economic to manufacture.
Cables of this kind comprise, inside a sheath, a single reinforcing member and generally a single housing such as a tube in which the optical fibers are disposed. The sheath is extruded over the tube and the reinforcing member, which are positioned near each other.
2. Description of the prior art
For example, international application WO 96/15466 teaches an economic cable having the structure described above. The reinforcing member, the tube and the sheath are all of circular section. It appears that if this cable is curved the tube can be stressed in compression or in traction, according to the direction of the curvature. The skilled person is well aware that optical fibers must absolutely not be subjected to stress in traction. Any such stress increases the attenuation and reduces the lifetime of the fibers.
The present invention therefore consists in a cable comprising a housing in which optical fibers are disposed, this simple and economical cable having a structure such that the fibers are subjected to virtually no stresses if the cable is curved.